1. Field of the Invention
The present invention relates to a burglarproof device for vehicle useful to prevent a burglary in a vehicle propelled by an internal combustion engine such as a car, a two wheeler, a marine vessel or a jet propelled ship.
2. Description of the Related Art
Conventionally, to start an engine for vehicle, a key switch for engine start is mechanically turned on, employing a cylinder key passed to the regular driver of vehicle alone. Accordingly, the engine start is impossible without a regular key, whereby the burglary of the vehicle is prevented. However, even though the vehicle burglary is prevented relying on the key, it is not necessarily possible to fully attain a burglarproof effect because the key is relatively easily duplicated.
Thus, there is a system for enhancing the burglarproof effect, in which the information designating a key for vehicle is sent from the key to the key cylinder, and the key cylinder identifies the sent information and permits the start of engine only if the regular information is identified, as disclosed in JP-B-4-15141, for example.
Specifically, a set of magnetic circuits is provided, consisting of a key coil wound around an axial core inside the key that is placed in proximity to a rotor coil wound around an annular core disposed around the periphery of a key insertion hole in the key cylinder, whereby the information for driving the engine is passed via this set of magnetic circuits between the key and the key cylinder.
However, the conventional burglarproof device for vehicle attained some effect to prevent the burglary of the vehicle, but had a problem of taking a trouble of inserting and turning a key into the key cylinder also serving as an electrical switch. Because of the operation of inserting and turning a key into the key cylinder, it had another problem that the start of engine was not permitted at a location away from the vehicle or a mechanical failure was likely to occur.
Also, when the driver left the vehicle with the key inserted into the key cylinder, no burglarproof unit was provided.
Also, in starting the engine at night, the driver could not see an insertion hole for the key cylinder in the darkness, taking a lot of time to start the engine. To solve this problem, a measure for placing a lamp in the key cylinder may be taken, but especially in the case of cheap two wheelers, it was not preferable that the lamp was installed, because the cost was increased.
Moreover, the design near the driver's seat was aggravated owing to the existence of the key cylinder.